1. Field of the Invention
The present invention relates to a gas separation membrane and a gas separation membrane module. More specifically, the present invention relates to a gas separation membrane which is capable of being made into a spiral type gas separation membrane module while maintaining high permeability and a gas separation membrane module which has the gas separation membrane.
2. Description of the Related Art
A material formed of a polymer compound has a gas permeability specific to the material. Based on this property, it is possible to cause selective permeation and separation out of a target gas component using a membrane formed of a specific polymer compound (gas separation membrane). As an industrial use aspect for this gas separation membrane related to the problem of global warming, separation and recovery from large-scale carbon dioxide sources with this gas separation membrane has been examined in thermal power plants, cement plants, or ironworks blast furnaces. Further, this membrane separation technique has been attracting attention as a means for solving environmental issues which can be achieved with relatively little energy. In addition, the technique is being used as a means for removing carbon dioxide from natural gas mainly including methane and carbon dioxide or biogas (biological excrement, organic fertilizers, biodegradable substances, sewage, garbage, fermented energy crops, or gas generated due to anaerobic digestion).
The following methods are known to be used for securing gas permeability and gas separation selectivity by making a site contributing to gas separation into a thin layer to be used as a practical gas separation membrane. A method of making a portion contributing to separation serving as an asymmetric membrane into a thin layer which is referred to as a skin layer, a method of using, as materials having mechanical strength, a support and a thin film composite provided with a selective layer contributing to gas separation which is disposed on the support, or a method of using hollow fibers including a layer which contributes to gas separation and has high density is known.
As typical performances of a gas separation membrane, a gas separation selectivity shown when a target gas is obtained from a mixed gas and a gas permeability of a target gas are exemplified. For the purpose of enhancing the gas permeability, gas separation membranes for which various materials are used have been examined.
For example, JP1991-262523A (JP-H03-262523A) describes a composite oxygen-enriching membrane formed by forming a specific oxygen permeating polymer membrane on at least one surface thereof using a polyorganosiloxane membrane that contains large silica zeolites as a support. Further, JP1991-262523A (JP-H03-262523A) describes that the oxygen permeating polymer membrane does not contain zeolites.
A molecular sieve is known as a compound having characteristics similar to those of zeolites. For example, paragraph [0048] and claim 15 of US2008-0295692A describe a method of providing a layer such as of polysiloxane or thermosetting silicone rubber on a mixed matrix membrane of a molecular sieve (molecular sieve polymer) that is functionalized by a polymer.
Moreover, JP4551410B describes that a mixed matrix membrane, which includes a continuous-phase organic polymer and a molecular sieve such as silicoalumino phosphate (SAPO) having a specific molar ratio of silica to alumina, is used as a gas separation membrane.